Liion batteries feature ~135kw/kg. this is very good. GM's 1996
electric vehicle used lead-acid batteries getting 25kw/kg and
performed at industry standard, except for a 79 mile range. with 5.3X
as much battery power, the new electric vehicle can have substantially
greater performance.

furthermore, supercapacitors are much like batteries.

Beyond this still, METAL HYDRIDES are much like batteries. They are
basically big metal batteries like nickel metal hydrides, that hold
hydrogen for power. installing these metal hydrodes in cars or gadgets
is one of the easiest ways to store power.

i bet a piezoelectric handcrank or dynamo could recharge it using
water. it is an infinitely reversible chemical reaction and holds
hydrogen 2-3x as densely as liquid hydrogen, and will never explode.
power.

William Bunker